Cam grinding machine



Oct. 9, 1962 c. s. YINGST CAM GRINDING MACHINE 7 Sheets-Sheet l OriginalFiled April 22, 1958 S e R n W MW M W.

Oct. 9, 1962 c. s. YINGST 3,057,120

CAM GRINDING MACHINE Original Filed April 22, 1958 7 Sheets-Sheet 2 ourINVENTOR. Cyrus 5. Yin'gst BY mm 213% 1952 c. s. YINGST CAM GRINDINGMACHINE '7 Sheets-Sheet 3 Original Filed April 22, 1958 INVENTOR. Cyrus5. Yingst BY J Oct. 9, 1962 c. s. YINGST 3,057,120

CAM GRINDING MACHINE IN V EN TOR.

Cyrus 5. Yingst 1962 c. s. YINGST CAM GRINDING MACHINE Original FiledApril 22, 1958- '7 Sheets-Sheet 5 T. 5 p mdJ e Tn N T e WY 0 8 N S 5rlllu U QI/ WJ r7 W m Oct. 9, 1962 c. s. YINGST CAM GRINDING MACHINEOriginal Filed April 22, 1958 '7 Sheets-Sheet 6 INVENTOR Cyv-us S.Yz'ngst B United States Patent F 3,057,120 CAM GRINDING MACHINE Cyrus S.Yingst, Cincinnati, Ohio, assignor to The Heald Machine Company,Worcester, Mass, a corporation of Delaware Continuation of applicationSer. No. 730,105, Apr. 22, 1958. This application Sept. 30, 1960, Ser.No. 60,261 20 Claims. (Cl. 51-101) This invention relates to a camgrinding machine and more particularly to apparatus arranged to finishnoncircular cylindrical surfaces and the like by grinding. Thisapplication is a continuation of my patent application Serial Number730,105 filed April 22, 1958, now abandoned.

In the generation of surfaces of revolution of noncircular cross-sectionwith a grinding machine, it is usual practice to move the wheel radiallyinwardly and outwardly in response to the movement of a follower passingover the surface of a master cam which has the same general shape as thesurface to be generated. The chief difficulty encountered with thismethod of operation is that, as the wheel wears or is dressed, asuitable compensation must be made for the fact that the relationshipbetween the surface of the follower and the surface of the wheel hasbeen changed. Several methods have been proposed in the past foraccomplishing this compensation but none of them have proved to beentirely adequate. The difiiculties which have been experienced with theprior art machines of this type have been obviated in a novel manner bythe present invention.

It is, therefore, an outstanding object of the present invention toprovide a cam grinding machine having automatic compensation for wheeldress and wear.

Another object of this invention is the provision of an internal camgrinding machine of the follower type in which compensation is made fordressing of the wheel.

A still further object of the present invention is the provision of acam grinding machine including interlocked cycling equipment forregulating the operation of the apparatus.

It is another object of the instant invention to provide a cam grindingmachine of rugged desgn which will require a minimum of maintenance andwill give a long life of useful service.

A further object of the invention is the provision of a cam grindingmachine which is capable of grinding its own master cams.

Another object of the invention is the provision of a cam grindingmachine providing for the use of hydraulic power in clamping andunclamping the workpiece.

Although the novel features which are believed to be characteristic ofthis invention will be particularly pointed out in the claims appendedhereto, the invention itself as to its objects and advantages, the modeof its operation, and the manner of its organization may be betterunderstood by referring to the following description taken in connectionwith the accompanying drawings forming a part thereof, in which:

FIGURE 1 is a perspective view of a cam grinding machine embodying theprinciples of the present invention,

FIGURE 2 is a vertical sectional view of a portion of the apparatustaken on the line IIII of FIGURE 1,

FIGURE 3 is a horizontal sectional view of the apparatus taken on theline IIIIII of FIGURE 2,

FIGURE 4 is a vertical sectional view of the apparatus taken on the lineIVIV of FIGURE 3,

FIGURE 5 is a vertical sectional view of the apparatus taken on the lineVV of FIGURE 3,

FIGURE 6 is a schematic view of certain hydraulic and pneumatic circuitsassociated with the invention, and

3,051,120 Patented Oct. 9, 1962 FIGURE 7 is a graphical illustration ofthe path of movement taken by the grinding wheel during the grindingcycle.

In the description which follows, the expression longitudinal andtransverse are used to indicate those directions relative to the axis ofthe grinding wheel of the machine.

Referring first to FIGURE 1, wherein is best shown the general featuresof the invention, the grinding machine, indicated generally by thereference numeral 10, is shown as comprising a base 11 on which ismounted a wheelhead 12 adapted to support and rotate a cylindrical grinding wheel 13. A feed mechanism 14 of theusual type is associated withthe wheelhead to provide for transverse advancement of the wheel intothe workpiece. Also mounted on the base 11 is a workhead 15 consistingof a housing 16 on which is mounted a motor 17. Also included in theworkhead 15 is a screw compensating apparatus 13; a follower mount 19,and a bridge 21. Mounted on the base 11 is a control housing 22containing the usual electrical, hydraulic, and pneumatic controls. Thewheelhead 12 rests on a wheelhead table 20 which is mounted forlongitudinal motion on the base 11 and slides under the workhead 15 in agap formed by a suitable recess 23 formed in the base 11 and bridged bythe bridge 21. The screw compensating mechanism 18 is immovably fixed onthe bridge 21 and therefore remains fixed relative to the base 11. Thehousing 16, however; is suitably mounted in a manner which will bedescribed further hereinafter for transverse sliding motion relative tothe bridge 21 and to the base 11. It is not, however,- capable oflongitudinal motion relative to the members. The follower housing 19 issuitably mounted on the screw compensating mechanism 18, as will bedescribed more fully hereinafter, and is capable of longitudinal motionrelative thereto but is not capable of transverse motion; its movement,therefore, is similarly determined with respect to the bridge 21 on thebase 11.

Referring now to FIGURE 2, the base 11 is shown with its recess 23 andthe bridge 21 mounted across the recess 23. The screw compensatingmechanism 18 is shown firmly mounted on the bridge 21, and connected bythe screw 24 to the follower housing 19. The main housing is shown ashaving a rear wall 25 and a bottom wall 26 which rests on transverseways solidly mounted on bridge 21. The bottom wall 26 has a firstportion 27 and a second portion 28 each of which is mounted for slidingin the usual way on hardened steel rails 29 and 31, respectively,mounted on the bridge 21. A considerable space separates the first andsecond portions of the bottom wall 26. The screw compensating mechanism18 is provided with two vertical walls 32 and 33. The wall 32 extendsoutboard of the first portion 27' of the bottom wall 26 of the mainhousing 16. The vertical wall 33, however, extends downwardly to thebridge 21 through the gap between the first portion 27 and the secondportion 28 of the bottom wall 26. Mounted between the first portion 27and the second portion 28' of the bottom wall 26 of the main housing 16is a support 34. A suitable V-way is formed on the face of the firstportion 27 of the bottom wall in the part thereof which faces the otherportion; a lug 35 extends from the support 34 to engage the V-way. Asimilarly formed abutment 36 extends from the other side of the support34 to engage the gib 37 which rests on a supporting bridge 103 formed aspart of the horizontal wall connecting portions 27 and 28 of the mainhousing 16. The gib 37 is formed with an inclined surface which engagesa similarly formed surface on the abutment 36 and is adjustable by meansof a screw 55 which extends through the portion 28 of the bottom wall 26of the main housing. It can be seen, then, that the support 34 iscapable of transverse movement on occasion relative to the base 11.

The housing 16 is provided with a hinged connection to a motor supportplate 39. The motor support plate is capable of pivotal movement about ahorizontal axis passing through the rear wall 25 of the housing. Themain housing 16 is also provided with a front wall 41 which carries asplit ring 42. This ring is adapted to carry a rotating and transverselyslidable element which will hereinafter be referred to as the slidehead, comprising a yoke 63 having diametrically opposite journals 64 and65 slidably arranged in the split ring 42, a workpiececarrying ring 61consisting of a journal 138 and work carrier plate 139 attached theretoat the right side with a master cam 43 at its left side. The journal 138and the plate 139 define an annular groove 62 around the periphery ofthe ring 61. The master cam is of a generally tubular constructionhaving V-shaped grooves 44 formed on its outer surface for engagement bya V-belt drive and on its inner surface is formed with a conical mastersurface 45, whose average or pitch line is in the shape of the desiredcam to be ground.

Mounted in the follower housing 19 is a shaft 46 carried for rotativemovement in suitable bearings. The right end of the shaft 46 extendsfrom the housing 19 and has mounted thereon a follower 47 having afrusto-conjcal surface for engagement with the master surface 45 of themaster cam 43. The shaft 46 is not capable of longitudinal motion withinthe housing 19 and at its left end it is provided with a recess 48permitting the entrance of the screw 24. Fastened to the end the housing19 is a nut 49 having threads which closely engage the screw 24 which isalso provided with a back-lash take-up member 51 of well-knownconstruction. The screw compensating mechanism housing 18 is providedwith a gear box 52 and the screw 24 is provided with a shaft portion 53which is carried in suitable hearings in the gear box 52 for rotationrelative thereto. A hand wheel 54 is mounted on the left hand end of theshaft portion 53 as it extends from the gear housing 52.

Mounted in the key support 34 is a key 56 of elongated form having adownwardly depending shaft 57 which is suitably mounted in bearings forrotation in the support 34. A lock nut provides for adjustment of thebearings on the shaft 57.

In FIGURE 3 it can be seen that a dressing tool 58 is integrally joinedto the housing 16 and moves with it transversely of the base. In thisfigure is also shown a diagonal slot 59 in which the key 56 resides. Theslide is formed in the bottom portion of the follower housing 19, as isbest shown in FIGURE the slot is, of course, set at a substantial angleto the axis of the shaft and coincides with the angle of the follower47.

The yoke 63 is provided with integral journals 64 and 65 extending fromdiametrically opposite sides there-of. The split ring 42 is providedwith bores 66 and 67 adapted to receive the journal 64 and 65,respectively. The journal 65 is provided at its outer end with a piston68 which is carried in a cylinder 69. Adjustable stop screw '11 extendsthrough the wall 41 into the bore 66 in opposition to the end of thejournal 64. The stop screw 71 is actuated by a crank handle 72accessible from the front of the machine. A portion of the journal 65 isreduced to form a reduced portion 73 and an oil passage enters theportion of the bore 67 occupied by the reduced portion 73. A passage 74extend through the reduced portion 73 and intersects a longitudinalpassage 75 extending axially through the journal and terminating in agroove 76 formed in the cylindrical surface of the yoke 63 where itengages a groove 137 in journal 138. The groove 137 is connected by ahole to a longitudinal passage 77 which, in turn, leads to one side of aworkpiece holder 78 (shown best in FIGURE 6) which normally occupies theright hand side of the plate 139. Similarly, the journal 64 is providedwith a reduced portion 79 to which an oil passage has access through thehousing 16, the reduced portion being provided with a passage 81extending entirely therethrough. The passage 81 intersects a boreextending longitudinally of the journal 64 and terminating inwardly in agroove 83. The groove 83 is connected by small passages to alongitudinal passage 84 leading to the workpiece holder 7 8 in a mannerwhich will be described more fully hereinafter.

Referring now to FIGURE 5, the motor plate 39, as has been shown, ishinged to the top of the rear wa1l25 of the main housing 16. The otherside of the plate 39 is supported by the top part of a forward wall 85of the housing by means of an adjustable connecting screw 86 to permitleveling of the motor 17 and to permit the adjustment of belt tension.The motor output shaft is connected through flexible belts 87 to theinput shaft of a gear reduction unit 88, the output shaft of which isconnected through V-belt 89 to the grooves 44 forming the outer surfacesof the master cam 43. In FIGURE 5 is very well shown the manner in whichthe bridge 21 straddles the recess 23 in the base 11 and permits thewheel head table 29 to pass in the space left thereby between. At itsforward side the key support 34 is provided with a threaded section 91encasing a screw 92 which is supported by bracket 146 attached toportion 85 of the housing 16 and adjustable by means of a hand wheel 93(see FIGURE 3). As is evident in this figure, there are two sets ofgi-bs 37 at widely spaced points bearing on opposite ends of the support34.

An abutment 94 extends upwardly from the bridge and is engaged by theend of a piston rod 95 actuated by a piston 96 residing in a cylinder 97formed in the lower part of the main housing 16. It can be seen that thefollower mount 19 is mounted for longitudinal sliding motion on ahorizontal extension 98 of the compensating mechanism housing 18. Thisextension 98 appears in FIGURE 2 as being connected to the verticalwalls 32 and 33 and is supported by these walls. FIGURE 5 shows verywell how the bottom wall 26 of th main housing 16 is divided into aforward portion 99 and a rearward portion 161 through which thesupporting wall 33 extends in order to engage key 56 with diagonal slot59. This figure shows the manner in which a bridge 1412 extendsdownwardly from the portion 99 to receive the gib 37 while a similarbridge 103 extends downwardly from the portion 161 to receive the othergib 37.

In FIGURE 4 it can be seen that the gear box 52 0f the compensatingmechanism housing 18 is provided with a cylinder 164 in which isslidably received a piston 165. The piston 105 is provided with a pistonrod 166 having rack teeth 167 formed thereon and slidably mounted in abore 108. At the upper part of the gear box is mounted a threaded stop169 which engages the end of the piston rod. The stop 169 is adjustableaxially of the bor 198 and indicia are formed thereon to determine aproper setting, as will be described hereinafter. The rack teeth 107 ofthe piston rod 106 engage a segmental pinion 111 which is free to rotateon a hub extension of the gear housing 52. A ratchet wheel 112 mountedon the shaft 53 and keyed thereto is engaged by a pawl mechanism 113which acts to rotate the ratchet wheel 112 in one direction of movementonly.

In FIGURE 6 the work piece holder 78 is shown as having a series ofclamps 114 for clamping a workpiece 115. Each clamp is an extension ofthe piston rod of one of the pistons 116 which is slidably movable inits individual cylinder 117. When the workpiece holder 78 is fastened tothe plate 139, as it normally is, the right hand end of each cylinder117 is connected to the oil passage 77 while the left hand end of eachcylinder 117 is connected to the passage 84 formed in the journal 138. Apressure oil line 118 is connected to a source of oil under pressure,not shown, while a drain line 119 returns the oil to a sump, not shown.The line 118 is attached to a four-way solenoid valve 121. A drain line.5 119 is connected to the drain ports of this valve. One output port ofthe valve 121 is connected by a line 123 to the follower compensationcylinder 104, while the other output port of the valve 121 is connectedby a line 124 to the upper end of the same cylinder. The line 124 isconnected by a line 125 to the rearward end of the back-lash cylinder97, the forward end of which is connected by a line 126 to the drainline 119. A conduit 127 is connected to a source of air under pressureand through a solenoid-actuated valve 128 to the rearward end of thecylinder 69. The valve 128 includes an actuating coil 129. An opening atthe forward end of the cylinder 69 permits the escape of air forward ofthe cylinder 68. A line 131 connects the pressure oil line 118 to oneside of a manual-type, four-way valve 132 having an actuating handle,not shown, which is readily accessible to the opera-tor of the machine.One output port of the valve 132 is connected by a line 133 through thehousing 16 and various passages to the passage 77 associated with theworkpiece holder 78. The other output port of the valve 132 is connectedby a line 134 through the housing 16 and various passages to the passage84 and the workpiece holder 78. The last port of the valve 132 isconnected by a line 135 to the drain line 119.

It will be understood that the machine contains many elements that arenecessary for its operation but which form no part of present inventionand, therefore, have not been described in detail. For instance, meansare provided for moving the wheelhead table 29 and the wheelhead 12 onan extended longitudinal traverse to withdraw the wheel from theworkpiece to cause it to enter the workpiece, and to cause is to passover the dressing tool 58 on occasion. Also, means is provided forreciprocating the wheel in the workpiece during the grinding operation,as is the usual practice in such machines. Furthermore, it will beunderstood that the feed mechanism 14 associated with the wheel head fortraversing the wheel 13 laterally of the head of the machine is alsoprovided with various switches and actuating mechanisms for bringinginto play various par-ts of the grinding cycle. For instance, at asuitable time a switch will be actuated to energize the coil 122 of thesolenoid valve 121 and the coil 129 of the valve 128.

The operation of the invention will now be readily understood in view ofthe above description. Let us now assume that workpiece has just beenfinish ground; the table 20 carrying the wheelhead 12 has run out to thefar right or rest position. At point H the table 20 operates a switch136 which sets the compensating cycle in motion. Solenoids 129 and 122of valves 128 and 131, respectively, all are energized. Air in cylinder69 goes to exhaust, releasing pressure from the piston 68, and,therefore, releasing the force between the master cam 45 and thefollower 47. The plunger in the valve 121 shifts, allowing oil in thelines 124 and 125 to go to exhaust via line 119. This releases pressureon the rearward side of the piston 96 and on the abutment 94. Thisfurther releases the pressure between the key 56 and the diagonal slot59 in which key 56 resides. Pressure oil from line 118 passing throughline 123 has reached the lower side of the cylinder 104 causing thecompensating piston 105 to move upwardly in the cylinder 104, so thatthe teeth 107 on the piston rod 106 engages the teeth on the segmentalpinion 111 and move the segment a predetermined amount, the amount beingdetermined by the setting of the compensation adjusting screw 109. Thepinion operates the pawl mechanism 113 to actuate and rotate the ratchetwheel 112. This turns the screw 24 and moves the follower housing 19 andthe follower 47 to the left in FIGURE 2. This movement causes the meandiameter of the follower 47 to 'be reduced so that the master cam 44will have its surface 45 somewhat closer to the axis of the shaft 46 atall times during its rotation. Referring to FIGURE 3, it will be seenthat the movement of the follower housing 19 to the left (carrying theslot 59 with it) causesmovement of the key 56 toward the forward part ofthe machine; since the key is mounted in the support 34, this lattermember travels to the right in FIGURE 5. Since the screw 92 engages athreaded portion of the support 34 and is constrained at its outersupport by being fastened to front portion of the housing 16, housing 16thus moves to the right on the base 11 and carries the dressing tool 58with it. It will be understood, of course, that the follower housing 19is mounted on an extension 98 of the compensation housing 18 which, inturn, is bolted to the bridge 21 and does not partake of this movement.When the table reached the point H and set the compensation cycle inmotion, as aforementioned, the operator of the machine removes thefinished workpiece 115 from the work holder 78 and replaces it with aworkpiece which is to be finished. To accomplish this, the valve 132 isshifted manually to such a position that pressure oil from the line 118passes through the line 131 and the line 134 to the passage 84 and theinner end of pistons 116. This moves the clamps 114 to their outwardposition, thus releasing the old or finish workpiece 115. When the newworkpiece is in place, the operator again shifts the valve 132 manually,causing the pressure oil to appear in the passage 77 and at the outerends of the cylinders 117 to cause the clamps 114 to move inwardly andhold the workpiece.

The operator now moves a suitable lever to start the table 20 carryingthe wheelhead 12 and wheel 13 toward the grinding position. The movingof the lever causes the closing of a switch, not shown, whichdeenergizes the coils 129 of the valve 128 and also the coil 122 of thevalve 121. Valve 128 causes air pressure to enter the cylinder 69forcing the piston 68 forwardly to engage the trunnion 65 on the yoke63. The yoke 63 carries the journal 138 with master cam 43 and the workholding means 78 and is moved forward until the surface 45 of the mastercam 43 engages the surface of the follower 47, and presses the surfacesfirmly together.

The de-energization of the coil 122 and the movement of the valve 121causes pressure oil to flow to the upper side of the cylinder 104through the line 124, causing the piston 195 and the rod 106 to movedownwardly, resetting the compensating mechanism for the nextcompensation. Pressure oil also flows to the rearward end of thecylinder 97 through the line 125. This causes the piston rod to pressfirmly against the abutment 94 which, it will be remembered, extendsupwardly from the bridge 21. This pressure, of course, tends to push thehousing 16 rearwardly on the base and is in direct opposition to theforces between the key 56 and slot 59; the net effect of the action ofthe piston 96 and the cylinder 97 is to remove any lback-lash that mayexist between the key 56 and the slot 59. As the table travels towardthe grinding position, an interlock is provided to assure that the airpressure in the cylinder 69 is up to full pressure before the workheadmotor 17 starts rotating in order to prevent slippage between the mastercam surface 45 and the follower 47. As the motor begins to drive themaster cam 43 at a suitable speed,- the master cam rotates with thejournal 138. Since the plate 139 attached thereto carries the"work-holding means 78, both the master cam and the work-holding meansrotate and move transversely in unison.

The axis of the follower 47 remains stationary, although the followeris, of course, rotating in the shaft bearings. The yoke 63, carrying thejournal 138, partakes of a transverse motion by sliding on the journals64 and 65, thus duplicating the shape of the surface 45 of the mastercam. While this is happening, the wheel 13, having reached point B, hasentered the work piece and is now rough grinding the non-circular bore.It does so with a reciprocating motion as the work surface is presentedto it through the motions imparted by the master cam surface 45. Roughgrinding continues to the point C where an electrical contact in thefeed box 14 causes the table to run out, lowering the dressing tool intoposition. Since the housing 16 has been moved slightly forwardly on thebase as a result of the compensating cycle, the dressing tool haspartaken of the same movement and, therefore, removes a small amountfrom the surface of the wheel 13 in a dressing operation. It is well tonote that at this point the diameter of the dressed wheel has the samediameter as the mean diameter of the follower 47 which contacts themaster cam surface 45. The wheel now re-enters the bore at point E andcontinues reciprocating and feeding during the finish grind, which isthe period between point E and the point P. At the point P the feed isstopped and any further grinding takes place only because of theflexture of the wheel spindle during a spark-out; usually the sparkoutperiod is determined by a timer included in the feed mechanism 14. Atthe end of the spark-out period, when the workpiece is finished, thetable 20 starts to run out to its rest position. At point G an electricswitch is actuated, cutting off the power to the workhead motor 17 andde-energizing the solenoid of a brake on the motor shaft, thus causingthe workhead to stop. As the table arrives at point H, the compensationcycle is again initiated for grinding the next piece.

While certain novel features of the invention have been shown anddescribed and are pointed out in the annexed claims, it will beunderstood that various omissions, substitutions and changes in theforms and details of the device illustrated and in its operation may bemade by those skilled in the art without depatring from the spirit ofthe invention.

The invention having been thus described, what is claimed as new anddesired to secure by Letters Patent l. A cam grinding machine,comprising a base, an abrasive wheel, a wheelhead carrying the wheel andmounted on the base for movement in the direction of the wheel axis, aworkhead housing mounted on the base for lateral movement only, means tobring about relative lateral feeding movement between the wheelhead andthe housing, a follower mounted on the base for longitudinal movementonly, a yoke having horizontal journals slidably mounted in the housingfor horizontal movement only, a ring mounted in the yoke for rotationonly relative thereto about an axis parallel to the axis of the wheel,means for rotating the ring, means for mounting a workpiece on a side ofthe ring facing the wheelhead, a master cam mounted on a side of thering facing the follower, the follower and master cam having engagingsurfaces which are inclined to the axis of the wheel, and means to bringabout the said longitudinal movement of the follower to compensate forreduction of wheel diameter.

2. A cam grinding machine, comprising a base, an abrasive wheel, awheelhead carrying the wheel and mounted on the base for movement in thedirection of the wheel axis, a wheelhead housing mounted on the base forlateral movement only, means to bring about relative lateral feedingmovement between the wheelhead and the housing, a follower mounted onthe base for longitudinal movement only, a yoke and a ring mounted inthe housing, the ring being mounted in the yoke for rotation about anaxis parallel to the axis of the wheel, means for rotating the ring, theyoke being capable of lateral sliding movement relative to the housing,means for mounting the workpiece on a side of the ring facing thewheelhead, a master cam mounted on a side of the ring facing thefollower, the follower and master cam having engaging surfaces which areinclined to the axis of the wheel, a cylinder connected to the yoke tocontinuously press it in one direction of lateral movement so that thecam is continuously pressed against the follower, and means to bringabout the said longitudinal movement of the follower to compensate forreduction of wheel diameter.

3. A cam grinding machine, comprising .a base, an abrasive wheel, awheelhead carrying the wheel and mounted on the base for movement in thedirection of the wheel axis, a workhead housing mounted on the base forlateral movement only, a truing tool fastened to the housing, means tobring about relative feeding movement between the wheelhead and thehousing, a follower mounted on the base for longitudinal movement only,a yoke and a ring mounted in the housing, the ring being mounted in theyoke for rotation about an axis parallel to the axis of the wheel, theyoke being capable of lateral sliding movement relative to the housing,means for mounting a workpiece on a side of a ring facing the wheelhead,a master cam mounted on a side of the ring facing the follower, thefollower and master cam having engaging surfaces which are inclined tothe axis of the wheel, means to bring about the said longitudinalmovement of the follower to compensate for reduction of wheel diameter,and means associated with the follower to move the said housing andtruing tool laterally when the longitudinal movement of the followertakes place.

4. A cam grinding machine, comprising a base, an abrasive wheel, awheelhead carrying the wheel and mounted on the base for movement in thedirection of the wheel axis, a workhead housing mounted on the base forlateral feeding movement only, means to bring about relative lateralfeeding movement between the workhead and the housing, a followermounted on the base for longitudinal movement only, a yoke and a ringmounted in the housing, the ring being mounted in the yoke for rotationabout an axis parallel to the axis of the wheel, means for rotating thering, the yoke also being capable of lateral sliding movement relativeto the housing, means for mounting a workpiece on the side of the ringfacing the wheelhead, a master cam mounted on a side of the ring facingthe follower, the follower and master cam having engaging conicalsurfaces which are inclined to the axis of the wheel, and means to bringabout the said longitudinal movement of the follower so that the averagepoint of contact with the surface of the master cam is moved laterallyto compensate for reduction of wheel diameter.

5. A cam grinding machine, comprising a base, an abrasive wheel, awheelhead carrying the wheel and mounted on the base for movement in thedirection of the wheel axis, a workhead housing mounted on the base forlateral movement only, means to bring about relative lateral feedingmovement between the wheelhead and the housing, a follower mounted onthe base for longitudinal movement only, a slide head comprising a yokehaving horizontal journals slidably mounted in the housing forhorizontal movement only, a journal mounted in the yoke for rotationonly relative thereto about an axis parallel to the axis of the wheel;means for rotating the journal of the slidehead, means for mounting aworkpiece on a side of the slide head facing the wheelhead, a master cammounted on a side of the slide head facing the follower, the followerand master cam having engaging surfaces which are inclined to the axisof the wheel, a cylinder connected to the yoke to continuously press itin one direction of the lateral movement so that the master cam iscontinuously pressed against the follower, and means to bring about thesaid longitudinal movement of the follower to compensate for wheeldiameter.

6. A cam grinding machine, comprising a base, an abrasive wheel, awheelhead carrying the wheel and mounted on the base for movement in thedirection of the wheel axis, a workhead housing mounted on the base forlateral movement only, a truing tool fastened to the housing, means tobring about relative feeding movement between the wheelhead and thehousing, a follower mounted on the base for longitudinal movement only,a slide head comprising a yoke having horizontal journals slidablymounted in the housing for horizontal movement only, a journal mountedin the yoke for rotation only relative thereto about an axis parallel tothe axis of the wheel; means for rotating the journal of the slide head,means for mounting a workpiece on a side of the slide head facing thewheel head, a master cam mounted on a side of the slide head facing thefollower, the follower and master cam having engaging surfaces which areinclined to the axis of the wheel, means to bring about the saidlongitudinal movement of the follower to compensate for wheel diameter,and means associated with the follower to move the said housing andtruing tool laterally when the longitudinal movement of the followertakes place.

7. A cam grinding machine, comprising a base, an abrasive wheel, awheelhead carrying the wheel and mounted on the base for movement in thedirection of the wheel axis, a workhead housing mounted on the base forlateral movement only, means to bring about relative feeding movementbetween the wheelhead and the housing, a follower mounted on the basefor longitudinal movement only, a slide head comprising a yoke havinghorizontal journals slidably mounted in the housing for horizontalmovement only, a journal mounted in the yoke for rotation only relativethereto about an axis parallel to the axis of the wheel; means forrotating the journal of the slide head, means for mounting a workpieceon a side of the slide head facing the wheelhead, a master cam mountedon a side of the slide head facing the follower, the follower and mastercam having engaging conical surfaces which are inclined to the axis ofthe wheel, and means to bring about the said longitudinal movement ofthe follower so that the average point of contact with the surface ofthe master cam is moved laterally to compensate for reduction of wheeldiameter.

8. A cam grinding machine, comprising a base, an abrasive wheel, awheelhead carrying the wheel and mounted on the base for movement in thedirection of the wheel axis, a workhead housing mounted on the base forlateral movement only, a truing tool fastened to the housing, means tobring about relative lateral feeding movement between the wheelhead andthe housing, a follower mounted on the base for longitudinal movementonly, a yoke and a ring mounted in the housing, the ring being mountedin the yoke for rotation about an axis parallel to the axis of thewheel, means for rotating the ring, the yoke being capable of lateralmovement relative to the housing, means for mounting a workpiece on aside of the ring facing the wheel, a master cam mounted on a side of thering facing the follower, the follower and master cam having engagingsurfaces which are inclined to the axis of the wheel, a cylinderconnected to the yoke to continuously press it in one direction oflateral movement so that the master cam is continuously pressed againstthe follower, means to bring about the said longitudinal movement of thefollower to compensate for reduction of wheel diameter, and meansassociated with the follower to move the said housing and truing toollaterally when the longitudinal movement of the follower takes place.

9. A carn grinding machine, comprising a base, an abrasive wheel, awheelhead carrying the wheel and mounted on the base for movement in thedirection of the wheel axis, a workhead housing mounted on the base forlateral movement only, means to bring about relative lateral feedingmovement between the wheelhead and the housing, a follower mounted onthe base for longitudinal movement only, a yoke and a ring mounted inthe housing, the ring being mounted in the yoke for rotation about anaxis parallel to the axis of the wheel, means for rotating the ring, theyoke being capable of lateral sliding movement relative to the housing,means for mounting a workpiece on a side of the ring facing thewheelhead, a master cam mounted on a side of the ring facing thefollower, the follower and master cam having engaging conical surfaceswhich are inclined to the axis of the wheel, a cylinder connected to theyoke to continuously press it in one direction of lateral movement sothat the master cam is continuously pressed against the follower, andmeans to bring about the said longitudinal movement of the follower sothat the average point of contact with 19 the surface of the master camis moved laterally to own pensate for reduction of wheel diameter.

10. A cam grinding machine, comprising a base, an abrasive wheel, awheelhead carrying the wheel and mounted on the base for movement in thedirection of the wheel axis, a workhead housing mounted on the base forlateral movement only, a truing tool fastened to the housing, means tobring about relative lateral feeding movement between the wheelhead andthe housing, a follower mounted on the base for longitudinal movementonly, a yoke and a ring mounted in the housing, the ring being mountedin the yoke for rotation about an axis parallel to the axis of thewheel, means for rotating the ring, the yoke being capable of relativesliding movement relative to the housing, means for mounting a workpieceon a side of the ring facing the wheelhead, a master cam mounted on aside of the ring facing a follower, the follower and master cam havingengaging conical surfaces which are inclined to the axis of the wheel,means to bring about the said longitudinal movement of the follower sothat the average point of contact with the surface of the master cam ismoved laterally to compensate for reduction of wheel diameter, and meansassociated with the follower to move the said housing and truing toollaterally when the longitudinal movement of the follower takes place.

11. A carn grinding machine, comprising a base, an abrasive wheel, awheelhead carrying the wheel and mounted on the base for movement in thedirection of the wheel axis, a workhead housing mounted on the base forlateral movement only, a truing tool fastened to the housing, means tobring about relative lateral feeding movement between the wheelhead andthe housing, a follower mounted on the base for longitudinal movementonly, a slide head comprising a yoke having horizontal journals slidablymounted in the housing for horizontal movement only, a journal mountedin the yoke for rotation only relative thereto about an axis parallel tothe aXis of the wheel; means for rotating the journal of the slide head,the slide head also being capable of lateral sliding movement relativeto the housing, means for mounting a workpiece on a side of the slidehead facing the wheelhead, a master cam mounted on a side of the slidehead facing the follower, the follower and master cam having engagingsurfaces which are inclined to the axis of the wheel, a cylinderconnected to the yoke to continuously press it in one direction oflateral movement so that the master cam is continuously pressed againstthe follower, means to bring about the said longitudinal movement of thefollower to compensate for reduction of wheel diameter, and meansassociated with the follower to move the said housing and truing toollaterally when the longitudinal movement of the follower takes place.

12. A cam grinding machine, comprising a base, an abrasive wheel, awheelhead carrying the wheel and mounted on the base for movement in thedirection of the wheel axis, a workhead housing mounted on the base forlateral movement only, means to bring about relative lateral feedingmovement between the wheelhead and the housing, a follower mounted onthe base for longitudinal movement only, a slide head comprising a yokehaving horizontal journals slidably mounted in the housing forhorizontal movement only, a journal mounted in the yoke for rotationonly relative thereto about an axis parallel to the axis of the wheel;means for rotating the journal of the slide head, means for mounting aworkpiece on a side of the slide head facing the wheelhead, a master cammounted on a side of the slide head facing the follower, the followerand master cam having engaging conical surfaces which are inclined tothe axis of the wheel, a cylinder connected to the yoke to continuouslypress it in one direction of lateral movement so that the master cam iscontinuously pressed against the follower, and means to bring about thesaid longitudinal movement of the follower so that the average point ofcontact with the 11 surface of the master cam is moved laterally tocompensate for a reduction of wheel diameter.

13. A cam grinding machine, comprising a base, an abrasive wheel, awheelhead carrying the wheel and mounted on the base for movement in thedirection of the wheel axis, a workhead housing mounted on the base forlateral movement only, a truing tool fastened to the housing, means tobring about relative feeding movement between the wheelhead and thehousing, a follower mounted on the base for longitudinal movement only,a yoke and a ring mounted in the housing, the ring being mounted in theyoke for rotation about an axis parallel to the axis of the wheel, meansfor rotating the ring, the yoke being capable of lateral slidingmovement relative to the housing, means for mounting a workpiece on aside of the ring facing the wheelhead, a master cam mounted on a side ofthe ring facing the follower, the follower and master cam havingengaging conical surfaces which are inclined to the axis of the wheel, acylinder connected to the yoke to continuously press it in one directionof lateral movement so that the master cam is continuously pressedagainst the follower, means to bring about the said longitudinalmovement of the follower so that the average point of contact with thesurface of the master cam is moved laterally to compensate for reductionof wheel diameter, and means associated with the follower to move thesaid housing and truing tool laterally when the longitudinal movement ofthe follower takes place.

14. A cam grinding machine, comprising a base, an abrasive wheel, awheelhead carrying the wheel and mounted on the base for movement in thedirection of the wheel axis, a workhead housing mounted on the base forlateral movement only, a truing tool fastened to the housing, means tobring about relative lateral feeding movement between the wheelhead andthe housing, a follower mounted on the base for longitudinal movementonly, a slide head comprising a yoke having horizontal journals slidablymounted in the housing for horizontal movement only, a journal mountedin the yoke for rotation only relative thereto about an axis parallel tothe axis of the wheel; means for rotating the journal of the slide head;means for mounting a workpiece on the side of the slide head facing thewheelhead, a master cam mounted on a side of the slide head facing thefollower, the follower and master cam having engaging conical surfaceswhich are inclined to the axis of the wheel, means to bring about thesaid longitudinal movement of the follower so that the average point ofcontact with the surface of the master cam is moved laterally tocompensate for reduction of wheel diameter, and means associated withthe follower to move the said housing and truing tool laterally when thelongitudinal movement of the follower takes place.

15. A cam grinding machine, comprising a base, an abrasive wheel, awheelhead carrying the wheel and mounted on the base for movement in thedirection of movement only, a journal mounted in the yoke for rotationonly relative thereto about an axis parallel to the axis of the wheel;means for rotating the journal of the slide head, means for mounting aworkpiece on the side of the slide head facing the wheelhead, a mastercam mounted on a side of the slide head facing the follower, thefollower and master cam having engaging conical surfaces which areinclined to the axis of the wheel, a cylinder connected to the yoke tocontinuously press it in one direction of lateral movement so that themaster cam is continuously pressed against the follower, means to bringabout the said longitudinal movement of the follower so that the averagepoint of contact with the surface of the master cam is moved laterallyto compensate for reduction of wheel diameter, and means associated withthe follower to move the said housing and truing tool laterally when thelongitudinal movement of the follower takes place.

16. A grinding machine for finishing a cam with an abrasive wheel,comprising a wheelhead carrying the wheel and mounted on the base formovement in the direction of the wheel axis, a workhead housing mountedon the base for movement perpendicular to the wheel axis, a truing too'lmounted on the housing, a feed mechanism to bring about relative feedingmovement between the wheelhead and the housing, a follower mounted onthe base for movement parallel to the wheel axis, a slide head mountedin the housing for rotation about an axis of the wheel, the slide headhaving journals and a power cylinder to cause a biased lateral slidingmovement relative to the workhead, means for mounting a master cam onthe slide head, the follower and master cam having engaging conicalsurfaces, a piston actuating a ratchet and pawl mechanism, the saidmechanism rotating a screw and nut mechanism to bring about the saidparallel movement of the follower to cause the master cam to engage alaterally-displaced portion of the follower to compensate for reductionof wheel diameter, and a key and inclined slot connection between thefollower and the housing to move the housing and truing tool laterallyduring the longitudinal movement of the follower.

17. A grinding machine for finishing a cam with an abrasive wheel,comprising a base, a wheelhead carrying the wheel and mounted on thebase for movement in the direction of the wheel axis, a workhead housingmounted on the base, means to bring about relative feeding movementbetween the wheelhead and the housing, a follower mounted on the base, ayoke mounted in the housing and capable of lateral sliding movement onlyrelative thereto, a ring mounted in the yoke for rotation relativethereto, a master cam mounted on one side of the ring for engagementwith the follower, a hydraulically-activated workpiece-holding means onthe other side of the ring, the yoke having diametrically opposedjournals which reside in sliding relationship in recesses formed in thehousing, a first hydraulic passage extending through the housing intoone of the recesses, a second passage in the corresponding journalcommunicating at one end with the first passage, and a groove formed inthe surface of the ring leading to the workpiece-holding means and incontinual communication with the other end of the second passage.

18. A grinding machine for finishing a cam with an abrasive wheel,comprising a base, a wheelhead carrying the wheel and mounted on thebase for movement in the direction of the wheel axis, a workhead housingmounted on the base, means to bring about relative feeding movementbetween the wheelhead and the housing, a follower mounted on the base, ayoke mounted in the housing and capable of lateral sliding movement onlyrelative thereto, a ring mounted in the yoke for rotation relativethereto, a master cam mounted on one side of the ring for engagementwith the follower, a hydraulically-activated workpiece-holding means onthe other side of the ring, the yoke having diametrically opposedjournals which reside in sliding relationship in recesses formed in thehousing, the workpiece-holding means having a clamping piston, a firsthydraulic passage extending through the ring, communicating at one endwith one side of the said piston, and terminating at the other end inthe outer periphery of the ring, a second hydraulic passage extendingthrough the ring, communicating at one end with the other side of thepiston, and terminating at its other end in the outer periphery of thering, the first and second passages being located at axially-spacedpositions on the ring, the passages opening into corresponding annulargrooves formed in the yoke, a third passage extending through one of theyoke journals and opening at one end into one of the grooves, a fourthpassage extending through the other journal and opening at one end intothe other groove, and means for selectively connecting the third andfourth passages to hydraulic pressure and drain to move the clampingpiston in one direction or the other.

19. A cam grinding machine, comprising a base, an abrasive wheel, awheelhead carrying the wheel and mounted on the base for movement in thedirection of the wheel axis, a Workhead housing mounted on the base forlateral movement only, a truing tool fastened to the housing, means tobring about relative lateral feeding movement between the wheelhead andthe housing, a follower mounted on the base for longitudinal movementonly, a slide head slidably mounted in the housing for horizontalmovement and mounted for rotation about an axis parallel to the axis ofthe wheel, means for rotating the slide head, means for mounting aworkpiece on the side of the slide head facing the wheelhead, a mastercam mounted on a side of the slide head facing the follower, thefollower and master cam having engaging conical surfaces which areinclined to the axis of the Wheel, means to bring about the saidlongitudinal movement of the follower so that the average point ofcontact with the surface of the master cam is moved laterally tocompensate for reduction of wheel diameter, and means associated withthe follower to move the said housing and truing tool laterally when thelongitudinal movement of the follower takes place.

20. A cam grinding machine, comprising a base, an abrasive Wheel, awheelhead carying the wheel and mounted on the base for movement in thedirection of the wheel axis, a Workhead mounted on the base, a truingtol mounted on the base for lateral movement only, means to bring aboutrelative lateral feeding movement between the wheelhead and theworkhead, a follower mounted on the base for longitudinal movement only,a slide head slidably mounted in the workhead for horizontal movementand mounted for rotation about an axis parallel to the axis of thewheel, means for rotating the slide head, means for mounting a workpieceon the side of the slide ead facing the Wheelhead, master cam mounted ona side of the slide head facing the follower, one of the follower andmaster cam having a conical surface which is inclined to the axis of thewheel, means to bring about the said longitudinal movement of thefollower so that the point of contact with the surface of the master camis moved laterally to compensate for reduction in wheel diameter, andmeans associated with the follower to move the truing tool laterallywhen the longitudinal movement of the follower takes place.

References Cited in the file of this patent UNITED STATES PATENTS2,583,363 Durland Jan. 22, 1952 2,592,875 Durland Apr. 15, 19522,701,432 Kent Feb. 8, 1955 2,723,499 Dix Nov. 15, 1955 FOREIGN PATENTS159,602 Sweden July 9, 1957

